Internal combustion engine plant



June 25, 1935. A. BUCHI INTERNAL COMBUSTION ENGINE PLANT Filed Oct. 26,1929 4 Sheets-Sheet 1 7 a 4 Q Q 4 W a w 0 m L. I 0 m QH LK/W U 7 M v m wlv w a. a. W @1 2 Z 3 m A Z .G G G M 0h: H H fi a w M w H A .f w V 8 J rW a w H Q a 2 f J w. W. w 1 i zm: fi r o o a h J 1 V i P M m 1.. ms 6 m2 ,p a a W m HMU y .2 M G m 1 l M? M L pk A r M 2 H m T T0 HTHOSPl/EEEJune 25,1935. A. BUCHl 2,005,321

INTERNAL COMBUSTION ENGINE PLANT Filed Oc t. 26, 1929 '4 Sheets-Sheet 2June 25, 1935.- A. BUCHI INTERNAL COMBUSTION ENGINE' PLANT Filed Oct.26,, 1929 '4 Shets-Shee t :5

firinc/ amer 1-6-2-6-4-10-5-9-3-7' ER g m June 25, 1935. I A. BUCHI fINTERNAL COMBUSTION ENGINE PLANT Filed Oct. 26, 1929 4 Sheets-Sheet 4fizz/en for? reimumg r' 2,005,82l

- cosmus'non ENGINE by i i am-ea lsh hi, winterthue, swiisei-i na i'piieiiienoeiebeezeJ19zs, Serial N na-:22 1 Iii-Switzerland November 3,

. This {in ention relates to internal 'combustionthat since: periodicdecrease of exhaust presengines having exhaustv turbi'n'est for charging*sureis illustrated; I

. purposes 1. .e. engines which are provided withan ,Fig."3' shows-a,curve indicating the pressure in -exhaust turbine and a compressor. Inthe exhaust conduit oi. the engine according to H '5the'methodacoordi'figto the invention'thepresthis invention-ascomparedwith the charging I decreased-pressure is producedin the exhaust con- Yangl of the exhaust-gases is influenced 'invthat a pressure. the exhaustperiod being 180 crank duit between thecombustion cylinders-and the Fig.3a shows a curve similar to Fig. 3 except turbine-by.periodicallyopening the saidexhaust that a larger periodic decrease or exhaustpresio 'conduit. For producing the decreasedpressure sure isillustrated; 1|

. a periodically opening valve member may be ar-' Fig. 4 shows amodified form of a two at ranged between the combustion cylinders andthe exhaust turbine; turbine by way of whichexhaust gas may be dis- Fig.5 illustrates a further embodiment or the charged so that at least'apart of the exhaust invention;

' i turbine is by-passed. The method may be so carv Fig. 6 shows a il F8- ried into eil'ect that the decreased pressure is Fig. 7 is an endview of the engines 01' Figs. 1 produced in the vicinity of thedead-centre foland 5 showing particularly mechanism for operlowing theexhaust period which in two stroke ating a valve member; and a cycleengines is the lower dead center and in Fig. BI diagrammaticillustration n Secti n four stroke cycle engines isthe upper deadcenter. of the upper portion of a cylinder 01' a tour-cycle 2. 'Ihedecrease or pressure inthe exhaust pipe may en in f Old art win h p i in of the be of such intensity as to permit or being utilized Valveduring the scavenging p i d; V for scavenging the combustion cylindersor the Fi 9 illustrates a r mm i lly he relative exhaust conduitrespectively by means of the, positions of the inlet and exhaust V v heP1 compressed charging air.- The periodically actutons and a turbineby-pass valve for a tour-cycle 2i ated valve or gate member may beincluded in a n in n a by-pass which connects the exhaust conduit-be- 10illustrates dia ram at ally the relatween cylinder and turbine withthedischarge. tive positions or the i et a d us valv s, the conduitotthe turbine which leads'to the atmos- Pistons and a b ne Evy-Pm valvetor a twophere. Theperiodicaliy actuated valve member cycle e may becontrolled from the Diesel-engine: or, by Referring HOW t 1 0f thedrawings, I means or the pressure of the exhaust gases or by notes asingle t n te cy n bu ion e the charging pressure Alternatively, thesaid s comprising he cylinders 2--l I.v I2 is an valve member" may .becontrolled by the-mutual heust turbine which serves for di drivininfluence'fot the exhaust gas. pressure and the the charging Compressor-8 89868 a hargin ipres'sure; The control device of the of thecombustion engine p s into the turbine "valve member may be so way ofOOIldllil; and leave the designed that the latter may be completelyopened turbine through the conduit l5. Atmospheric air during thestartingfand th reversing of th is admitted to the charging compressorI; through so gine and. also when the latter runs at light loads. theconduit The PrewmPre-Ssed charge 4. 1n the accompanying drawings severalmbodb to the cylinders 2- of the combustion engine merits of the devicefor effecting the method acthrough the conFimt The essence of thecording to the invention are shown by way of ventionisembodiedintheparticular parts |2-2l.

I [8 denotes a periodically actuated valve or gate z gz g w 1 diagramsillustrating the member by means of which communication may 1 showsschematicallya combustion be efiected between the conduit l4 and thebypass 2|. 41 designates acam follower which zigisystemadaptedmr 16pm ofthe inven' serves for the actuation of the member II by means of the rod2!; In the construction shown P18. 2 shows a curve indicating the Pr 111in Fig. 1 the conduit II is connected with the 59 th xhaust duit or th nine ac di to discharge pipe is or the turbine which leads to thisinvention as C mp w h h h rg the open. A cam 46 driven by the engineraises P r he exhaust period being 72" c ank the follower 41 and rod 20against the compresangle; I v a sion of spring 48 which holds thefollower against Fig. 2a shows a curve similar to Fig. 2 except the cam.When a decreased pressure is to be produced in the conduit 14 the memberI 8 is opened so that at least a part of the exhaust gases present inthe conduit 14 is discharged.

The engine is 01 the ordinary two or four stroke cycle type and gets thewhole charge precompressed. The charge is further compressed in thecombustion cylinder, after ignition expansion follows and the combustiongases escape into a gas turbine. These exhaust gases are expanded tosubstantially atmospheric pressure in the gas turbine, so that in pipeI5 substantially atmospheric pressure prevails. Ahead of the gas turbinea pressure substantially above atmosphere pressure prevails. At the end0! the exhaust period the amount of the exhaust gases remaining in thecombustion cylinder should be as low as possible. The lower the pressureat this moment is, the smalleris the amount of the remaining exhaustgases. The incoming new chargegets only little heated if there is but asmall amount of remaining exhaust gases. When the member I. which may bea valve, a blast gate or the like is opened the high pressure part 01'the turbine or the whole turbine respectively is by-passed. Hence thepressure ahead of the turbine drops as soon as member I8 is opened. Thispressure drop expands with the velocity of sound (over 1000 i't./sec.)through the piping towards the combustion cylinders. The member I! isopened every time when one of the combustion cylinders is in the deadcenter position that follows the exhaust period. With two stroke cycleengines the piston is then in the inner dead center position and withfour stroke cycle engines the piston is in the outer dead centerposition. In the example illustrated in Fig. 1 member 16 would be opened10 times every 360 crank angle if the internal combustion engine is atwo cycle engine and member 18 would be opened 5 times every 360 crankangle ii the internal combustion engine is a four cycle engine.

In Fig. 2 the pressure variations under some conditions in the exhaustconduit l4 and the charging conduit l1 are illustrated. pt representsthe exhaust pressure in-the conduit H and m the pressure in the conduitI1. In the engine shown in Fig. 1, which is supposed to be a fourcycleengine, after every one-fifth of a revolution, corresponding to a crankangle of '12 lgnition takes place. Consequently the dead-centres at theend of the exhaust periods follow each other also in intervalscorresponding to an angular displacement of the cranks of 72. Accordingto the invention, in consequence of the opening of the member 18 in thevicinity of the said dead centres, a decrease of pressure is produced.pti indicates a small decrease of this kind. In Fig. 2a, line pt:indicates a large pressure decrease. The pressure pt: falls down to theatmospheric pressure pa. Thus the exhaust pressure pt, falls below thecharging pressure in during the interval 81 so that during thecorresponding time interval the combustion cylinders are scavenged bycharging air.

A similar decrease of the exhaust pressure and a scavenging may also beobtained with two cycle engines. This is accomplished by simultaneouslyuncovering the inlet and exhaust slots at the end of the combustionstroke as disclosed in page 1062 of the Zeitschrift des Vereinsdeutscher Ingenieure volume '10, No. 32. dated August 7, 1926.

In four cycle engines this decrease of the exhaust pressure is effectedin the conventional manner by keeping the inlet and exhaust valves ofthe cylinder simultaneously open during the scavenging period asillustrated in Fig. 8 of the accompanying drawings and supported inprinciple by a prior publication in the Swiss Patent No. 133,562. Inthis Figure 8, A refers to the admission valve, E to the exhaust valveand C to the cylinder.

Figs. 3 and 3a illustrate the pressure conditions in the exhaust conduitand intake manifold for a four-cylinder four-stroke cycle engine havingexhaust periods of approximately 180 crank angle. Fig. 3a illustratesthe possibility 01' increasing the period as well as the amount 01' thereduction 01' the exhaust pressure below the charging pressure. It willbe noted that the pressure line pt: extends further below line n(charging pressure) than line pt (Fig. 3) and that the period s: duringwhich the exhaust pressure is below charging pressure is longer thanperiod so (Fig. 3). pt: represents the exhaust pressure when the valvel8 opens every 180.

In the modified form of the two stage exhaust turbine shown in Fig. 4,22,23 denote the runners and 24, 25 the corresponding guide apparatus.The by-pass 2| leads from the conduit It to the front side of the guideapparatus 25 so that the exhaust gases passing through the same areenabled to transmit energy to the second wheel 23. In this type ofconstruction the valve member I8 is displaceable by the piston 21 whichslides in the cylinder 26. The one side of the piston 21 is acted uponby the pressureof the exhaust gases in the conduit and the other side bythe charging pressure in the conduit 29. The latter side is furtherinfluenced by the spring 23. The described device permits oi'pneumatically actuating the valve member I! in such a way that when thecharging pressure surpasses a certain amount the member I6 is opened andthe decrease of pressure in the exhaust conduit sets in. with theexhaust pressure rising, which is the case when a combustion cylinderdischarges in a relatively small exhaust conduit, the member I! isautomatically closed again.

Besides, in Fig. 4 a control member 33 is arranged by means of which themember I6 is manually operable so that the automatic operation may besuspended and the valve manually held open to by-pass part of theturbine when desired, as for instance, during starting of the engine.

In the constructional example illustrated in Figs. 5 and 6 anarrangement is shown by which the valve or gate member may be controlledby the mutual influence of the pressure in the charging compressor andthe exhaust pressure ahead of the turbine. The valve or gate member I 6is operated by a piston 21 displaceable in the cylinder 26, themovements of the piston 21 are influenced by the springs 26 and 26'. Oneend of the cylinder 26 is connected by the conduit 36 to the exhaustpipe I, a valve 34 is inserted in the conduit 30. A conduit 35 branchesof! the conduit 30 and leads into the atmosphere, a valve 36 is insertedin the conduit 36. The lower end of the cylinder 26 is connected by theconduit 29 to the discharge conduit I1 01 the compressor I3, a valve 31is inserted in the conduit 23, and a conduit 38 leading to theatmosphere and having a valve 33 branches oil the conduit 26. Theconduit 2i has two" branches, one branch 2| leads to the guide apparatus26 of the exhaust turbine 12 and has a valve 40 inserted in it and theother branch 4| is connected to the discharge pipe [5 of the turbine andis provided with a valve 42.

In Fig. the valves 34, 31 and 40 are open, the valves 36, 39 and 42 areclosed. The exhaust pressure in the conduits l4 and 33 acts on the upperside of the piston 21 and the pressure; of the compressed air on thelower side of said piston. Thus when the exhaust pressure is higherthan-the charging air pressure the valve or gate member I6 is closed,but as soon as the exhaust pressure drops below the pressure of thecompressed air the piston 21 is moved in the upward direction and theeduction member 18 is opened whereby a further decrease of the exhaustpressure occurs as part of the exhaust gases are bypassed through pipe2l into a low pressure stage of the turbine l2, or, when the valve 40 isclosed and the valve 42 opened, into the atmosphere. Before valve orgate member I8 is opened all the exhaust gases are conveyed through pipeI4 to the first stage of the turbine. After the valve or gate member isopened, part of the exhaust gases pass through pipe 2| into anotherstage of. the turbine where the pressure is lower, or-by opening valve42 may pass directly into the exhaust conduit I 6 leading from theturbine to the atmosphere. The pressure in pipe I 4 must thereforebecome lower when valve or gate 16 is open.

By these means the pressure in pipe l4 diminishes much quicker and theminimum pressure in the exhaust pipe 14 is much lower than without valvemember I8, as can be readily seen from Figs. 2, 2a, 3 and 3a,respectively. From Figs. 2, 2a., 3 and 311 can be seen that the longerthe valve member I3 is open, the longer the air pressure is above theexhaust pressure.

In the example shown, Fig. 5, all the exhaust gases pass through the lowpressure stage 25 of the exhaust turbine and from there through thecommon pipe I5 to the atmosphere. Blower l3 draws in through pipe I6 anddelivers into pipe I1.

The valves 34 and 31 serve for selectively closing the conduits 30 and23 respectively when it is desired to influence the device 26 solely bythe charging or the exhaust pressure respectively. If both valves areclosed this device is rendered entirely inoperative. In the latter casethe valves 36 and 33 serve for completely emptying the gas or air spaceswith which they are connected and prevent at the same time pressure fromunin-,

tentionally arising in the device 26 so as to influence the same due topossible leakage in the valves 34 and 31.

In Fig. 5 valves 34, 31 and 40 are shown in the open position, valves36, 33 and 42 in the closed position. Piston 21 in cylinder 26 isexposed to the force of spring 28 and the charging air pressure on oneside and to the force of spring 28 and the exhaust gas pressure on theother side. The valve 13 is open so long as the combined force of spring28 and the charging air pressure on the lower side of piston 21 isbigger than the forces on the upper side. By closing valve 31 andopening valve 33 atmospheric pressure prevails in the lower side of thepiston and the only force acting on piston 21 from this side isthe forceof spring 23. The force pushing valve|8 upwards is therefore smaller.The time during which the forces on the lower side of piston 21 arebigger than the force on the upper side becomes hence shorter andtherefore also the time during which valve I6 is open.

With valve 42 closed and valve 40 open, a pressure equal to that in thelow pressure part 25 of. the turbine l2 prevails in pipe 2|. Whenopening valve II, the pressure in exhaust pipe l4 can therefore not fallbelow the pressure of sure-controlled means are out of order..mechanical means comprise a cam 46, similar the low pressure turbinepart. Closing valve 40 and opening valve 42 connect pipe 21 directly tothe atmosphere, so that substantially atmospheric pressure may bereached in pipe l4 when opehin valve I8. I

Instead of working the valve l8 pneumatically, valve l8 may be operatedmechanically by means of earns 46, roller 41, pushrod 20, links 49, 50and 33. This latter method may also be provided for and applied in caseof a break down of the pneumatic operating device.-

The charging pressure increases only when the compressor and turbinerotate at a higher speed. The turbine rotates at a higher speed onlyafter the exhaust pressure is increased. Thus a charging pressure riseis only possible together with an exhaust pressure rise. The result,that the member l8 would remain open will therefore not obtain.

In order to fix the valve or gate member in any desired position thehand lever 33 is provided with an eye through which a pin 43 is thrust,the latter passing further through any one of the perforations 44provided on the plate 45 as is illustrated in Fig. 6.

By choosing springs 28 and 28' of suitable power the pressure requiredto operate the value or gate member may be varied at will and may a bechosen higher or lower than the actual pressure of the compressed air orof the exhaust gases respectively.

Besides the pressure-controlled means for opening the valve or gatemember l8 mechanical means for the same purpose are provided in theconstructional example shown in Fig. 5, which may, for instance, be usedwhen the pres- These to cam l9 hereinbefore referred to on the engineshaft with which a roller 41 at the lower end of a rod 20 cooperates. Aspring 48 presses the roller 41 into engagement with the cam 46. Theupper end of the rod 20 is connected by means of the one armed lever 49and link 56 to the handle 33 of the valve or gate member l8. The pin 5|coupling the lever 49 and the link 50 is placed in position if thismechanical device has to be operative and is withdrawn if thepressure-operated means has to operate the valve or gate member l8.

To get the pressure drop according to M1 valve 40 is open and valve 42is closed, the exhaust gases by-pass the high pressure part of theturbine only and escape into a pressure stage of the turbine with alower pressure but still above atmospheric pressure.

To get the pressure drop according to ptz valve 40' is closed and valve42 is opened. The exhaust gases by-pass' thereby the whole turbine andescape into conduit l5, where substantially atmospheric pressureprevails. Such a decrease of pressure in the exhaust pipe as describedis specially advantageous at the end of an exhaust period in that itpermits of emptying the combustion cylinders of the exhaust gases to alarge extent. Furthermore, it permits of creating such a large decreaseof pressure which lasts for a time interval of such length that a moreeffective scavenging of the combustion cylinders is effected than withthe means heretofore known.

I claim:

1. In a power plant comprising an internal combustion engine having aplurality of cylinders, a turbine driven by the exhaust gases of saidengine, a compressor for supplying compressed air to the combustioncylinders for charging and scavenging purposes, an air conduitinterposed between said internal combustion engine and said compressor,said compressor driven by said exhaust turbine, an exhaust conduitinterposed between internal combustion engine and turbine, a pluralityof combustion cylinders exhausting into said exhaust conduit, 21;by-pass connecting said exhaust conduit to the atmos- 2. In a powerplant comprising an internal combustion engine having a plurality ofcylinders, a turbine driven by the exhaust gases of said engine, a.compressor for supplying compressed air to the combustion cylinders forcharging and scavenging purposes and driven by said exhaust turbine, anexhaust conduit interposed between internal combustion engine andturbine, into said exhaust conduit exhausting a pluralityilmusdiearhznzsmicozrmdtitr ithznevd niiui mat mlei in [mm-u scom'ruiiii31 atrmiuiti.trtmnhmototlrasi'dieiok11.5 i

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